cmd/images: Disallow the input of image when using the -a option
cmd/images: Disallow the input of image when using the -a option

When using the --all option and having the image parameter input, an error should be returned.

```
➜  buildah git:(images-fix) sudo ./buildah images -a ubuntu
when using the --all switch, you may not pass any images names or IDs
```

Signed-off-by: Zhou Hao <zhouhao@cn.fujitsu.com>

Closes: #972
Approved by: rhatdan

nalind/buildah,rhatdan/buildah,TomSweeneyRedHat/buildah,ipbabble/buildah,nalind/buildah-1,rhatdan/buildah,nalind/buildah-1,TomSweeneyRedHat/buildah,nalind/buildah,ipbabble/buildah,nalind/buildah-1,projectatomic/buildah,TomSweeneyRedHat/buildah,projectatomic/buildah,rhatdan/buildah,projectatomic/buildah